Tribological Properties of AA2014+15NbAI_3and AA2014+15FeAI_2MMC's Materials on Extruded Condition and after Anodizing

摘要

Pin-on-disk apparatus was used on this work to test the tribological properties on AA2014+ 15% vol intermetallics (NbAl_3 or FeAl_2) Metal Matrix Composites (MMC's). Both materials were obtained through mechanical alloying of a powder mixture of Al, Cu, Si, Mg and NbAl_3 or FeAl_2, following by die pressing and hot extrusion. Microstructure of MMC's showed a well intermetallic distribution. Both materials showed a density as extruded condition close to 2,94g/cm3 and also a similar hardness (AA2014+15NbAl_3: 155HB, AA2014+15FeAl_2,164HB). Chromium Steel ball as well as alumina ball were used as a pin and load of 5N and 10N during 25m were used. Friction coefficient reaches high values when wear occurs due to a combination of abrasion and abrasion mechanisms on MMC's. Since aluminum alloys are commonly anodized, MMC's were tribological tested after using the Sulfuric Acid (SAA) and the Chromium Acid (CAA) process to anodizing. Friction coefficient behaviour showed an abrupt change after the anodizing layer is worn under certain sliding conditions.